Researchers discovered that exposure to highly energetic charged particles -- similar to those in the galactic cosmic rays that astronauts encounter on extended spaceflights -- hurt the central nervous system and cause thinking problems in lab animals.
"This is not positive news for astronauts deployed on a two- to three-year round trip to Mars," said Charles Limoli, a professor of radiation oncology at the University of California, Irvine School of Medicine.
"Performance decrements, memory deficits and loss of awareness and focus during spaceflight may affect mission-critical activities, and exposure to these particles may have long-term adverse consequences to cognition throughout life," Limoli said in a university news release.
The researchers reached their conclusion by studying rodents exposed to charged particles at a NASA lab. The exposure led to inflammation in the brain and disrupted brain signaling, they said. As a result, the rodents performed worse on tasks requiring learning and memory.
Limoli, working on behalf of NASA's Human Research Program, is among those investigating how space radiation affects astronauts. Learning how to mitigate those effects is essential to further space exploration, scientists say.
According to Limoli, travelers to Mars would face more trouble than those who work on the International Space Station because they'd face more galactic cosmic rays outside the protective magnetosphere of the Earth.
Spacecraft could be developed with better shielding, although there's no way to fully escape the cosmic rays, he said. Drug treatments that are under development also might help, he noted.
The study appears in the May 1 issue of Science Advances.